The present invention relates to an improved self-aligning roller bearing in which lubricant is infused into one or more of sliding surfaces respectively existing between an outer race and a floating ring, between a cage and a floating ring, between a floating ring and an inner race, between a cage and an outer race to thereby be able to improve the lubricating condition of the self-aligning roller bearing.
Conventionally, as a self-aligning roller bearing, there are known several types of self-aligning roller bearings: for example, a self-aligning roller bearing shown in FIGS. 1 and 2 structured such that, when it is used, an inner race 100 thereof can be rotated, and a floating ring 600 thereof is mounted on the outer peripheral surface 103 of the inner race 100; a self-aligning roller bearing shown in FIGS. 5 and 7 structured such that a floating ring 600 or a cage 500 thereof is mounted in the central portion of the raceway surface 204 of an outer race 200 thereof; and, a self-aligning roller bearing shown in FIGS. 3 and 4 structured such that, when it is used, an outer race 200 thereof can be rotated, a floating ring 600 thereof is mounted on the outer peripheral surface 103 of an inner race 100 thereof. By the way, in these figures, reference characters 300 and 400 respectively designate rollers.
In the self-aligning roller bearing shown in FIGS. 1 and 2, the floating ring 600 is mounted on the outer peripheral surface 103 of the inner race 100 with a very small clearance 700 between them, and the respective parts of the present roller bearing are lubricated by lubricant or lubrication oil which is supplied to the present roller bearing.
In the self-aligning roller bearing shown in FIGS. 3 and 4, a circumferential groove (lubrication oil groove) 102 is formed in the central portion of the inner peripheral surface 104 of the inner race 100, the inner race 100 is formed in such a manner that it includes a plurality of through holes (lubrication oil holes) 101 respectively formed on the circumference thereof for communicating the circumferential groove 102 with an outer peripheral surface 103, and the floating ring 600 is mounted on the outer peripheral surface 103 of the inner race 100 with a very small clearance 700 between them. Therefore, lubricant or lubrication oil, which is supplied to the bearing from a shaft, is passed through the circumferential groove (lubrication oil groove) 102 formed in the inner peripheral surface 104 of the inner race 100 as well as through the through holes (lubrication oil holes) 101, and is injected through the small clearance 700 between the inner peripheral surface 602 of the floating ring 600 and the outer peripheral surface 103 of the inner race to thereby lubricate the respective parts of the present roller bearing.
In the self-aligning roller bearing shown in FIG. 5, the outer race 200 includes a circumferential groove (lubrication oil groove) 202 formed in the central portion of the outer peripheral surface 203 thereof, and also a plurality of through holes (lubrication oil holes) 201 which are respectively formed in the circumference thereof for communicating the circumferential groove (lubrication oil groove) 202 with the raceway surface 204; and, the floating ring 600 is mounted in the central portion of the raceway surface 204 of the outer race 200 with a very small clearance 700 therebetween, while the floating ring 600 includes two flat portions 603 and 603 which, as shown in FIG. 6, are respectively disposed in the two mutually opposing positions of the circumference of the floating ring 600. Due to this structure, lubricant or lubrication oil, which is supplied to the circumferential groove 202 (lubrication oil groove) formed in the outer race outer peripheral surface 203, is passed through the through holes (lubrication oil holes) 201 and is injected through the clearance 700 between the outer race raceway surface 204 and the floating ring outer peripheral surface 601 to thereby lubricate the respective parts of the present roller bearing.
In the self-aligning roller bearing shown in FIG. 7, the outer race 200 includes a circumferential groove (lubrication oil groove) 202 formed in the central portion of the outer peripheral surface 203 thereof as well as a plurality of through holes (lubrication oil holes) 201 for communicating the circumferential groove (lubrication oil groove) 202 with the outer race raceway surface 204; and, the cage 500 is mounted on the central portion of the raceway surface 204 of the outer race 200 with a very small clearance 700 between them. In this structure, lubricant or lubrication oil supplied to the circumferential groove (oil groove) 202 in the outer race outer peripheral surface 203 is firstly passed through the through holes (lubrication oil holes) 201 and is then injected through the clearance 700 between the outer race raceway surface 204 and the cage outer peripheral surface 501, thereby lubricating the respective parts of the present roller bearing.
However, in the conventional structure shown in FIG. 1, since the clearance 700 between the floating ring outer peripheral surface 601 and the cage inner peripheral surface 502 as well as the clearance 700 between the inner race outer peripheral surface 103 and the floating ring inner peripheral surface 602 are small, the lubricant is difficult to advance into these clearances 700, so that the sliding surfaces can be easily damaged, for example, they can be easily scraped due to lack of lubrication.
In addition, in the conventional structure shown in FIG. 3, the floating ring 600 is structured such that it spreads over the inner race through holes (lubrication oil holes) 101, and the clearance 700 between the inner race outer peripheral surface 103 and the floating ring inner peripheral surface 602 is small, which provides a large resistance to the passage of the lubricant. For this reason, the lubricant, which is supplied from the shaft through the inner race 100, is not allowed to turn in the circumferential direction so that, as shown in FIG. 4, the lubricant can be injected only through the clearance 700 located in the neighborhood of the through holes (lubrication oil holes) 101 formed in the inner race 100.
Therefore, a required amount of lubricant cannot be supplied into the bearing under a normal oil pressure, with the result that the temperature of the present roller bearing becomes excessively high and the present roller bearing can be damaged, for example, can be scraped and so on due to lack of the lubrication oil quantity.
Similarly, in the conventional structure shown in FIGS. 5 and 7, because the floating ring 600 and cage 500 are so structured as to spread over the through holes (lubrication oil holes) 201 in the outer race 200 and also the clearance 700 between the outer race raceway surface 204 and floating ring outer peripheral surface 601 or cage outer peripheral surface 501 is small, there arises a problem to be solved due to lack of lubrication.